Muffler for internal-combustion engines



Feb. 7, 1928.

w. .IEHLE MUFFLR FOR INTERNAL COMBUSTION ENGINES Filed Dec. 6, 1926 K Patented Feb., 7, 1928-.

UNITED STATES PATENT oFF IC E WILHELM JVV'EHLE, OF DONAUESGHINGEN-KARLSHOF, GERMANY, ASSIGNOR 0F THIRTY -THREE AND ONE-THIRD PER CENT TQEMANUEL HERTZ, OF NEW YORK N. Y., AND THIRTY-THREE AND ONE-THIRD PEB, CENT T0 CARL HIRSCH, 0F

KREUZLINGEN. SWITZERLAND.

MUFFLER FOR INTERNAL-COKBUSTION ENGINES.

Application led December 6, 1926, Serial No. 152,957, and in Germany July 5, 1926.

My invent-ion relates to muliiers for internal combustion engines, particularly for motor-car engines, and it is an object of my invention to provide 'a muiler of the kin-d described in which the exhaust gases are cooled and expanded rapidly.

My muiiier is of the general type in which two sets of spiral passages are separated by a transverse partition. In order to effect the rapid cooling and expansion aforesaid; I provide slots in the'partition through which a certain percentage of the comparatively hot exhaust gases which have just entered the muftler, is allowed to mix with the coinparatively cool gases in the more remote parts of the muffler. The fresh gases, being under high pressure, flow at comparatively high speed and in mixing with the `cooler low pressure gases, give up to them a portion of their mechanical and thermic energy so that the cooler gases are accelerated by the hotter gases while, on the other hand, the hotter gases are cooled by contact with the cooler ones. In this manner, back pressure of the gases in the muffler is efficiently eliminated and the cooling action of the ambiant air is supplemented by the mixing of the hotter and cooler gas particles as described.

It is another object of my invention to provide a muffler vof the kind described which is simple in construction and therefore suitable for quantity production.v

ln` the drawings aixed to this specification and forming part thereof a muffler embodying my invention is illustrated diagrammatically by Way of example.

In the drawings Fig. l is an elevation, partly in vertical section, of the muier,

Fig. 2 is a plan view of the lower half of the muifier casing showing the transverse partition partly broken away.

Referring now to the drawings, a and c are the upper and lower halves of the muier casing. Each half constitutes a spiral passage and a top or bottom plate with corrugated depressions. z' is a transverse partition plate which is inserted between the two halves a and c., and k -is a screw by which the two halves a, e are connected, clamping the partition v1 between them. The spiral passages of the upper and lower halves of the casing are connected by a hole f in the partition z' which surrounds the central screw lo. Slots g are formed in the partition z' and Slots h are formed in the walls of the spiral passage of the lower half c. The object of these latter slots is similar to that of the slots g in the partition `z', that is, they tap a certain percentage of comparatively hot gas and allow it to mix with the cooler gas. An inlet pipe I) is connected to the upper half a of the casing and d is an exhaust pipe at the lower half c. Z are depressions between the reaches of the spiral passages in the casings a and 0 by which ambiant air is admitted so as to increase the cooling surface of the muiiler.

Preferably the slots g in the partition i and the slots h in the walls of the lower half c are so arranged that the central line of the slots extends through the centre of the adjacent slots g as will appear from Fig. 2.

The muliier operates as follows:

The exhaust gases are admitted to the passage of the upperhalf a through the pipe .7) and flow in this passage as far as the central hole 7 in the partition z'. On their way through the passage of the upper/half, a certain percentage of the comparatively hot gases which are under comparatively high pressure, escapes into the passage of the lower half c where the hot and high-pressure jets act on the cooled and expanded gases in the manner of an injector so as to eliminate back pressure. At the same time, the hot high-pressure jets from the slots g are cooled and expanded in contact with the cooled and expanded flow of gases in the lower half 0 so that theylose part lof their mechanical and thermal energy. A similar action is achieved by the slots 7i in the partitions between the reaches of the passage iny the lower half c. As the gases issuing from these slots are hotter and under higher pressure than those in the adjacent reach of the passage they will accelerate the gases and give up a poi-tion of their heat to them, as described. Due to the particular arrangement of the slots f/ with respect to' the slots it the jets from the slots /L- impinge on the jets from the slots tr/ in the partition z', exerting an intense cooling action on the comparatively hot jets from g.

The slots g inthe partition e' alsw the gases vto expand rapidly immediately upon their entering the mulier and at the same time they are intensely cooled. Back pressure in the muier is eliminated by t-he acceleration which the hotter andmore rapidlyy flowing gases impart to the cooler and more slowly flowing ones so that the gases are discharged rapidly and uniformly. Be-

i sides, a high percentage ofl the heavier constituents of the gases, oil vapours and the like, are condensed by the rapid cooling and the mechanical action of the slots so that smoke emission is reduced.

Another advantage of the muler v`according to my invention is the readiness with which it may be di-vided for inspection and cleaning, all that is required loeing unscrewing of the screw c. The pipes b and d may be arranged at any desired angleand a hole m is provided in one of the parts, for in-4 stance the lower half c which isengaged by a'pin m so that the two halves when connected will be in a given relative position.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown anddescribed for obvious modications will occur to a person skilled in the art.

I claim 1. An engine muiiier comprising a casing having depressions in opposite walls thereof, and a partition having a substantially central opening within said casing and dividing the same into separate sections, said sections having spiral passages communicating with each other through said central opening.

2. An engine muffler comprising a casing having depressions in opposite walls thereof,

and a partition having a substantially central opening Within said casing and dividing the same i'nto separate sections, said sections having -spiral passages communicating with each other through said central opening,

said partition having slots permittingcom-u munication between sections at points other than the central opening.

3. An engine muliier comprising a casing having depressions in opposite walls thereof, and a partition having a substantially central opening Within said casing and dividing the same into separate sections, said sections minating in an inlet and the outer end of the other passage terminating in an outlet, said partition and the walls ofsaid other spiral passage having complementary positioned slots for causing an intermixture of the hot and cold gases passing through the muffler.

5. An engine muiiier comprising a casing having inlet and outlet ports, a partition having a substantiall central opening within said casing and 'viding the same into separate sections, said sections having spiral passages communicating at their inner ends with each other through said central opening, the outer end of one of the passages terminating in the inlet port and the outer end of the other passage terminating in the outlet port, said partition and the walls of said other spiral passage having complementary,

positioned slots arranged so that the axis-of each slot in the walls intersects the axis of the adjacent slot in said partition.

6. An engine muiier comprising a sectional casing, a transverse partition having a. central opening in said casing and dividing the same into separate chambers, each of the chambers having a substantially coiled passage communicating at their inner ends with each other through said central opening, said partition and the walls of one of said chambers having complementary positioned slots therein for causing an intermingling of a portion of the hot and cold gases, and means detachably connecting said sections.

7. An engine muler comprising a sectional casing having depressions in the top and bottom thereof, a transverse partition having a central opening in said casing and dividing the same into separate chambers, each of the chambers having a spiral passage communicating at its inner end with said.v

central opening, the outer end of one of the passages terminating in an inlet port and the outer end of the other passage terminating in anoutlet port, means for detachably selcuring said sections to ether, and'means for causing a mixture of t e hot and cold gases at predetermined points within said other spiral passage.

8. An engine muier comprising a casing having inlet and outlet ports, a transverse partitlonin said casing dividing the same into separate sections, a` spiral passage formed in each of said sections, and communicating at their inner ends with each other, the outer en'd of one of said passages terminating in the inlet port and the outer end of the other passage terminating in the out-let port, and means Within said casin whereby the ases are expanded and coole i as they pass t rough the spiral passages.

Signed at Stuttgart, Germany, this 21st day of August A. D. 1926.

WILHELM Jrnanr..` A 

